Copiers, printers, and other multifunction machines, such as including scanning and facsimile capabilities, are familiar in offices. (As used herein, all such machines will be generically called “printers.”) A digital printer is typically a machine having both hardware and software aspects. Various of these aspects mandate that the machine undergo a distinct time period between the machine being turned on or otherwise requested to operate and the machine being ready to output prints. Among possible software aspects may be a need for an internal processor to “boot up” or otherwise become active; or an interpreter or equivalent program to process incoming image data to make the data directly useable by the hardware. Among possible hardware aspects are activating any number of motors or drives, such as to draw a print sheet into a position to receive an image. In the case of xerographic or electrostatographic printers, there is typically an appreciable “warm-up” time in which a fuser is brought to a necessary temperature, and/or a charging device is brought to a necessary potential. In the case of an ink-jet printer, there is typically a warm-up time in which, for instance, lines or channels for conveying liquid ink are primed, or a solid ink stick is partially melted to yield a useable quantity of liquid ink. In the case of an input scanner, which is usually part of a digital copier, there is typically a necessary warm-up time for an illumination lamp to reach a necessary luminescence.
It is generally known, in the office equipment industry, to provide systems by which a printer can have active and inactive modes. Clearly, a printer will be consuming more energy during an active state than an inactive state. In many cases, the warm-up time (whether literal or figurative) of a printer is itself a major consumer of time and energy, and therefore there is a desire to lessen the number of times a printer is requested to “wake up” in the course of a day.
U.S. Pat. Nos. 6,252,681; 6,805,502; and 6,819,445 propose methods of operating digital printers to enhance long-term performance.